Manufacture of electrical coils



0 L 1940- F. MARTINDELL MANUFACTURE OF ELECTRICAL COILS Filed July 13,1939 M'VtWTOR f: MART/NOE 7 Arm/em Patented Oct. 15, 1940 UNITED STATESMANUFACTURE OF ELECTRICAL COILS Frank Martindell, Western Springs, 111.,assignor to Western Electric Company, Incorporated, New York, N. Y., acorporation of New York Application July 13, 1939, Serial No. 284,163

'1 Claims.

This invention relates to the manufacture of electrical coils, and moreparticularly to electrical coils of the type in which sheets ofinsulating materialare interposed between successive superposed layersof windings.

Electrical coils of the type above referred to are usually wound inmultiple, that is, a plurality of such coils are wound simultaneously,in separated zones, upon a common winding spindle or mandrel. Theconvolutions of wire of each coil are wound in layers, superposed oneupon the other, and sheets of insulating material, common to all of thecoils, are inserted between successive layers without interrupting thewinding operation. After the required number of layers have beencompleted, the stick of coils is removed from the winding spindle andthen separated into individual coils by severing the severalinterleaving sheets between the spaced coils.

0 One of the chief difliculties encountered in connection with thewinding of electrical coils of the type referred to is in theintroduction and application of the interleaving sheets while the coilspindle is rotating at the high speed which is 25 necessary in order toobtain the desired economy in the manufacture of such coils. Heretofore,the insertion of the interleaving sheets at the desired spindle speedswithout wrinkling or producing other irregularities therein has beenexceedingly difficult, if not impossible, especially when employinginterleaving material that is extremely thin, as is desirable in orderto reduce the size of the coils and thereby conserve space in theapparatus in which the coils are employed. The principal difficultiesarise from the tendency of the forward or leading edge corners of theinterleaving sheets to curl or fold back due to such corners beingunsupported and free of the approaching on-coming wires until thesuperposed layer of wires is nearly completed. Such curling or foldingback of the leading edge corners of the interleaving sheets results inan undesired bulging, irregularity or unevenness in the end coils on thespindle, which sometimes renders 45 them unsuitable for commercial use.

An object of the present invention is to obviate the abovementioneddifliculties by providing an improved method of winding such coils, amethod in which an improved form of interleaving sheet is employed.

In accordance with the above object, one embodiment of the inventioncontemplates the pro- ,vision of an improved method of windingelectrical coils of the type referred to, and more par- 5 ticularly, amethod which employs interleaving sheets having their forward orleadingedge corners rounded or cut away and thus free of any tendency tocurl 01' fold back upon insertion of the sheets into a "stick or coilsbeing wound.

A more complete understanding of the invention may be had from thefollowing detailed description whenread in conjunction with theaccompanying drawing, in which:

Fig. 1 is a plan view of an interleaving sheet embodying the inventionand with the use of which the improved method may be practiced;

Fig. 2 is a perspective view of a partially wound stick of coils,showing an interleaving sheet in process of being inserted into theseveral coils, and 15 Fig. 3 is a perspective view similar to Fig. 2with the interleaving sheet completely wrapped around the several coils.

Referring to the drawing, there is illustrated in Figs. 2 and 3, awinding spindle or mandrel I0 upon which a plurality of electrical coilsII, II

are formed simultaneously by winding thereon, in separated zones, aplurality of superposed layers of wires l2, I2 drawn from a plurality ofsupply spools (not shown). Upon the completion of each layer of wire inthe several coils, an interleaving sheet l5 of insulating material isinserted therein to separate the superposed layers of wires. The sheetis wrapped around the several coils by the respective wires l2. When therequired number of layers of wire have been wound, the several coils onthe spindle are removed as an integral unit or stick which is laterseparated into individual coils by severing the several interleav ingsheets between the spaced coils.

Machines for producing sticks of electrical coils of the type abovereferred to are well known in the art and, therefore, furtherdescription thereof is unnecessary to a complete understanding of thepresent invention. In order that such coils may be manufacturedeconomically, it is necessary, as mentioned above, that the interleavingsheets be inserted without interrupting the high rotating speed of thewinding spindle.

According to a feature of the present invention, the forward or leadingedge It of each interleaving sheet I5 is provided with rounded or cutaway comers l1, l1. Thus, when the sheets are inserted into a "stick ofcoils being wound, with the leading edges of the sheets parallel to theaxis of the coils, as shown in Fig. 2, the leading edge corners ll ofthe sheets will closely adhere to the preceding layer of wires,

since the corner portions which otherwise would tend to curl or foldback are completely out away. The end coils on the spindle are thusformed just as smooth and uniform as the intermediate coils.

The trailing edge I! of each interleaving sheet is preferably formedwith corner portions II, II which are complementary to the inner edgecorners I1, so that when the sheet is completely wrapped around thecoils, the usual uniform amount of overlap is provided, as shown in Fig.3.

It should be understood that the invention is not limited to thespecific embodiments thereof herein illustrated and described, exceptinsofar as is defined by the appended claims.

What is claimed is:

i. A method of winding electrical coils, which comprises the steps ofwinding simultaneously in separated zones on a common winding spindle, aplurality of convolutions of wires in superposed layers. and insertingbetween successive layers without interrupting the winding operation, asheet of interleaving material having rounded corners at its leadingedge.

2. A new article of manufacture, comprising an interleaving sheet forinsertion between superposed layers of wires of a plurality of coilswhile being wound simultaneously in separated zones upon a commonspindle, said interleaving sheet being of a length sufficient tocompletely surround said layers, the leading edge of said sheet havingrounded comers and the trailing edge corners of said sheet beingcomplementary to said leading edge comers so as to slightly butcompletely overlap each other.

3. A method of winding a series of coils of alternate layers of wire andinsulating strips which comprises cutting away the ends of eachinsulating strip at the leading edge before theyarewoundandfeedingthestripeothatthe leading edge of the strip iscontacted first by the intermediate winding wires.

4. A method of winding simultaneously a series of coils of alternatelayers of wire and insulating strips which comprises rounding the endsof each insulating strip at the leading edge before they are wound, andfeeding the strip so that the leading edge of the strip between theroimded endsisgrippediirstbythecentralwindingwires.

5. A method of winding a series of coils of alternate layers of wire andinsulating strips upon a common spindle which comprises cutting away theends of each insulating strip before they are wound, and feeding thestrip so that the leading edge is parallel to the axis of thespindle'and is contacted ilrst by the intermediate winding wires.

6. A method of simultaneously winding a series of coils of alternatelayers of wire and insulating strips which comprises cutting away theends of each insulating strip at the leading edge before they are wound.and cutting the trailing edge of each insulating strip complementary tothe leading edge so that the leading and trailing edges completelyoverlap.

7. A method of winding a series of coils of alternate layers of wire andinsulating strips which comprises cutting away the ends of eachinsulating strip at the leading edge before they are wound, feeding thestrip so that the leading edge of the strip is contactedinitially by theintermediate winding wires, and cutting the trailing edge of eachinsulating strip complementary to the leading edge so that the leadingand trailing edges completely overlap.

FRANK MARTINDELL.

